Pellet mill



E. T. MEAKIN April 10, 1934.

PELLET MILL Filed Nov. 14, 1931 4 Shuts-Sheet l I VM\ 2% max R INVENTOR.EDGAR Z" Mam/1v A TTORNEYS.

E. "r. MEAKIN A ril 10, 1934;

PELLET MILL 4 Sheets-Sheet 3 Filed Nov. 14. 1931 INVENTOR.

EDGAR 7T MEAKIN ATTORNEYS.

Patented Apr. 10, 1934 UNITED STATES PATENT OFFICE PELLET MILL Edgar T.Mealrin, Berkeley, Calif.

Application November 14, 1931, Serial No. 574,944

18 Claims. (Cl. 107-8) My invention relates to a mill, and particularlyto a type of mill constructed to compress moldable material, whereby thematerial may be readily formed into pellets.

An object of my invention is the provision of a compact and durablemachine, having a large capacity, and which may be readily and eco-'nomically manufactured.

Another object of my invention is the provision of a device, of thecharacter described, in which parts may be quickly removed and assembledfor replacement or repair purposes, without causing undue tie-up of themachine.

Another object of the invention is the provision of a machine, employinga die plate through which material is forced to form the pellets, thedie plate being so mounted that it can be readily reversed when worn onone side, so as to positionthe other side for use.

Another object of my invention is the provision of a device, of thecharacter described, in which the use of a costly screw construction forforcing the material through a die is obviated.

An additional object of myinvention is the provision of an apparatus,particularly adapted for use in conjunction with the mill structure, forfeeding'material to the mill.

A further object of my invention is the provision of a device, of thecharacterdescribed, in which the structure is of such character as toallow facile and rapid adjustment of parts when this is desired.

The invention possesses numerous additional objects and features ofadvantage, some of which with the foregoing, will be set forthin thefollowing description of my invention.

Referring to the drawings:

Figure 1 is side elevation, partly in section, of the apparatus of myinvention.

Figure 2 is vertical sectional view of the mill and drive mechanismtherefor. Part of the structure is shown in elevation to discloseclearly the construction. 1 I

Figure 3 is a perspective view of one of the knives employed inconnection with the mill die.

Figure 4 is a horizontal sectional view taken in a plane indicatedbyline 4-4 of Figure 2.

Figure 5 is a side elevation, partly insection, of'the structureillustrated by Figure 4, looking in the direction indicated by arrow 5in Figure 4. I

Figure 6 is a. top plan view of one of the spreaders or plows used inconjunction with the mill rollers shown in Figures 2, 4 and 5.

Figure 7 is a vertical sectional view of the spreader, taken in a planeindicated by line 7-7 of Figure 6.

Figure 8 is a front elevational view of the spreader holder andguide.

Figure 9 is a vertical sectional view of the spreader holder, taken inaplane indicated by line 9-9 of Figure 8.

Figure 10 is a top planview of the mill drive mechanism, looking in thedirection indicated by arrow 10 in Figure 2.

Figure 11 is an elevational view of the inner end of the heater formingpart of the ap- 'paratus, looking in the direction of arrow 11 of Figure1.

Figure 12 is an elevational view of the outer end of the feeder formingpart of the apparatus, looking in the direction of arrow 12 of Figure 1.

Figure 13 is a sectional view of the mechanism for impartingintermittent motion to the feeder conveying screw, taken in a planeindicated by line 1313 of Figure 12. Part of the structure is shown inelevation and parts are omitted from the view to illustrate clearly theconstruction.

Figure 14 is a vertical sectional view of the cam used in connectionwith the structure illustrated by Figure 13.

It is desirable to form stock and poultry feed into suitable sizedpellets because this offers a clean and economical method of utilizingthe feed. The apparatus of my invention is particularly adapted for thispurpose; and in broadly descriptive terms it comprisesa bowl or pan, thebottom of which is formed by a die. Rollers are mounted on the die tocompress and force the material therethrough as it is fed into the bowl;and knives are mounted below the die to 'cut the strings of materialwhich are forced therethrough into suitable sized pellets. The die ismounted, in such manner and is of such construction, so that it may bereversed in position if one side becomes worn by continual contact withthe rollers; and the parts are arranged so that this operation may bereadily and easily performed. Suitable plows are mounted in the path ofmovement of the rollers for the purpose of spreading the materialuniformly over the die; and the rollers are mounted for bodily movementaway from the die, if adjustment or replacement thereof becomenecessary. A central shaft passing through the die is provided forsupporting the rollers and die; and means are also provided for causingrelative rotation between the die and the die.

Suitable means are provided for feeding proper quantities of material tothe bowl; and in the case it is necessary to apply heat to the materialto enhance compression and molding thereof, a heater is employed forthis purpose. In the formation of pellets of the character described, itis sometimes desirable to form them of more than one type of feeduniformly blended therethrough. For this purpose, the heater ispreferably provided with means for thoroughly mixing the material.

Mill structure With reference to the preferred modification of theapparatus of my invention, which I have chosen for detailed description,the mill structure comprises a housing of cylindrical shape, formed bythe lower section 2 and an upper section '3. Upper section 3 isprovided, adjacent the upper end, with a horizontally positioned Yinternal flanged support 4 having the centrally positioned hub 6 forminga bearing in which the vertical shaft '7 is journaled. A wear washer 8,upon which rests the large gear 9, is mounted on. the upper edge of hub6 and is journaled about shaft 7. Gear 9 is splined to the shaft, andthe upper edge of hub 11 of the gear is formed with a circular groove 12in which a split ring 13, mounted in a circular groove around shaft '7,is adapted to flt. From the preceding, it is apparent that, unlessotherwise supported, the split ring 13 and correlated structure willprovide a support for shaft '7 when the lower surface of the split ringbears on the hub 11, for a purpose to be later described.

Upper thrust bearing The upper end of shaft '7 is of reduced diameterand is journaled in a thrust hearing. The thrust bearing comprises athreadedhub 14 centrally positioned on the cover 16, the cover beingsecured to the upper end of section 3 and forming a gear box 17 betweenit and flange 4. A thrust nut cap 18, in which the upper end of shaft '7is journaled, is threaded in hub 14; and the lower edge of thrust nut18, is formed with a flange 19 between which and the thrust washer 21,roller bearings 22 are mounted. After thrust nut 18 has been turned tothe desired position, it is fixed by means of a suitable lock washer 23,adapted to be secured to the hub 14. It is to be observed that thrustwasher 21 is journaled about the reduced portion of shaft '7, and istherefore adapted to abut against the shoulder formed by the reducedportion, when shaft 7 is properly positioned.

Lower thrust bearing amt die Interposed between the mill housingsections is a conically shaped ring 24, having the outwardly projectingflange 26 on the lower edge thereof and positioned interior of the lowermill housing section. A die clamp 2'1 is removably mounted on flange 26and is provided with a shoulder 28 forming a support for the outer edgeof a relatively thick but flat and centrally apertured die plate 29, thedie being firmly held aga nst a shoulder formed in the lower inner edgeof ring 24. Seated in the central aperture of the die is a die block31,having upper and lower surfaces flush with those of the die plate andbeing formed with a downwardly projecting hub 32. Shaft '7 is formed, atits lower end, with a port on of reduced diameter and this portion-isjournaled for rotation in the die block, the inner edge of the blockadjacent the shaft having a recess within which is a suitable gasket 33flush with the upper surface of the block and die. A split ring 34fitting about hub 32 of the die block is positioned to bear against boththe under surface of die 29 and die block 31; and the ring 34 is fixedin position by means of a lock-nut cap 36 threaded onto hub 32. Thecover of lock-nut cap 36 has a large central aperture through whichshaft '7 projects, and the cap is of sufficient length to provide ahousing for the lower thrust bearing.

This thrust bearing structure includes a. ring 37 having a conicalundersurface and bearing against the under side of hub 32, a plate 38 inwhich the shaft is journaled and bearing against the conical surface ofring 3'7, roller bearings 39 adapted to roll against the under surfaceof plate 38, and a second plate 41 upon the upper surface of which therollers also bear. A thrust nut 42, projecting through the centralaperture in looknut cap 36, is threaded onto shaft '7 and bears againstthe under surface of plate 41 to hold the bearing structure. To lock theassembly, a lock washer cap 43, threaded onto shaft '7 and over thrustnut 42, and a lock nut 44 are provided.

From the preceding description, it is seen that the structure thus fardescribed can be assembled quickly by placing the upper end of shaft '7through bearing 6, slipping gear 9 thereover in proper position, andinserting split ring 13 in its groove on shaft '7, to hold the shaftfrom falling down. The upper thrust bearing is then assembled inapproximately the correct position; and then the lower thrust bearingand die supporting structure may be put together. During the assemblingof the latter structure, shaft '7 can move vertically to allow properpositioning of the parts; and after assembly of the lower thrust bearingand die, the upper thrust nut 18 may be turned to the proper positionand locked.

In case it is desired to remove the die plate 29 for replacement, thiscan be quickly and easily done, by removing'the die clamp 27, whichcomprises two semi-circular sections held together by bolts or inotherwords is a split ring, unscrewing 120 the lock-nut cap 36 a few turns,and removing the split ring 34. The die plate, having a central apertureof greater diameter than the diameter of lock-nut cap 36, can thus bereadily passed over the lock-nut cap. During such removal, the split 125ring 13 and correlated structure will prevent the shaft '7 from falling.Knives (for a purpose to be later described) are removably mounted onshaft '7, below the lower bearing and die; and it is obvious that theymust be removed first. Since the die-plate has the shape of a flat disk,if one surface thereof becomes worn by contact with rollers thereover,it may be reversed in position with great facility and used on the otherside. In order to allow access to the parts of the lower thrust 135bearing and die plate, lower section 2 of the mill housing is providedwith open sides 46, preferably along the entire length of the section.

Rollers 140 The conically sloped sides of ring 24 and the die supportedat the bottom thereof form a bowl, in which rollers 47 are caused torotate in order to compress and force material, fed into the bowl,through the die apertures. Preferably four rollers, equispaced aboutshaft 7, are provided. The rollers are journaled on the spindles 48forming radally projecting arms of a spider 49, which is splined forrotation with shaft .7. A flange 51 is formed integral with shaft 7 toprovide a support 150 for the spider 49; and the flange is preferablypositioned so that the rollers contact with the upper surface of the dieplate. Preferably, the rollers are of any suitable ballbearingconstruction and are each composed of parts readily removable forreplacement or repair purposes, as indicated by the section of one ofthe rollers shown in Figure 2.

A second spider 52 having radially projecting arms 53, positioned overspindles 48, rests on the spider 49 and is also splined for rotationwith shaft 7. To the ends of arms 53 are secured the downly projectingarms 54, having apertures in which the ends of spindles 48 are mounted.It is seen.

that both of the spiders are joined together, by the describedstructure, and since they are both splined to shaft 7, they can be movedvertically as a unit, opposite the large side apertures 56 in the uppersection-=8 of the mill housing, so that worn or broken-parts of therollers may be quickly and readily removed for repair or replacementpurposes. Means are provided for elevating the roller and spiderstructure, comprising-the nut 57, threaded onto shaft 7 and the splitring'58 secured to the nut and havingan inwardly projecting flange 59seated in a circumferential groove adjacent the top of spider 52. Whenthe nut 57 is turned downwardly, it will hold the rollers 47 in closecontact with the die. Should it be desired to allow a slight spacebetween the rollers and de, depending upon the character ofmaterialto'be forced through the die, it is to be noted that the nut 57and structure correlated for use,

therewith, offers a means for providing this adiustment.

Plows Means are provided for spreading the material fed into the bowl,uniformly in the path of movement of the rollers and to a uniform depthin front of the rollers, including a plow 61,for each roller. Withreference to Figures 4 through 9, each of the plows is 'U shaped, andhas an inwardly projecting flange 62 forming the 'upper surface, and anangled flange 63, at the bottom, provided with an inwardly projectingextension 64 disposed at an angle, so as to throw excess material awayfrom the inner side of the roller. Each of the plows is mounted in aU-shaped guide frame 66 secured, over the-rollers, to the side of arm 53of spider 5 2. The back of the guide frame is cut away leaving sides 67of triangular shape to allow roller clearance. Pins 68 are mounted,adjacent the top and bottom of frame 66, in apertures 69 formed in thesides 67 of the frame; and the front of plow 61 is adapted to bearagainst the pins. Plow 61 is supported in the guide frame, by means of abolt 71 threaded in flange 62 of the plow, and having a collar 72adapted to bear against the underside of an apertured ear 73, formed onthe upper edge of guide frame 66, through which ear the bolt 71 passes.The upper end of the bolt projects through a hub 74, resting on the ear73, and to which the bolt is keyed; and a sprocket 76 is formed on hub74'. A handle 77 is secured to the top of the bolt, to provide means forraising or lowering the lower edge of the plow above the die, and thusregulate the depth of material in assembly. By turning handle 77, thedesired adjustment for all of the plows can thus be readily obtained.

tion with shaft 7, are provided for cutting the material forced throughthe die into pellets. The knives are preferably circular and have stems8-2 on the underside thereof, the lower portion of each stem being ofreduced diameter to provide a shoulder 83. A spring 84 surrounds thereduced portion of each stem; and the springs are resiliently pressedbetween the shoulders 83 and the bottom of housings 86, formed at theupper end of the upwardly projecting knife supporting arms 87, so as toresiliently press the knives against the undersurface of the die. Arms87 are formed integral with a hub 88 keyed to the end of shaft 7, thehub being locked in position by a lock nut 89 threaded onto the shaft.

When the pellets are formed, they are collected by a hopper 91,positioned below the die, and may be gathered by any suitable means,such as an endless conveyor 92 (Figure l) passing through the apertures46 in the mill housing.

Mill drive mechanism As seen from the preceding description, therollers, spiders therefor and knives are mounted for rotation with shaft7. This is accomplished by turning the gear 9, splined to shaft 7. Withreference to Figures 2 and 10, the driving means includes a suitableprime mover 93 such as an electric motor, secured to the upper part ofthe mill housing, having the rotatable shaft 94, which carries the smallsprocket 96. A sprocket chain 97 connects the large sprocket 98 with thesprocket 96, the large sprocket being secured to the vertical shaft 99journaled on the gear housing 17. Shaft 99 also carries a small pinion101, which meshes with gear 9, to effect rotation thereof, upon startingof the prime mover.

To the hub of gear 9 is secured a bevel gear 102, meshing with the bevelgear 103 mounted on the horizontal shaft 104, projecting throughv thewall of the mill housing, and journaled therein and in the bearing 106secured to the inner wall of the housing. The outer end of shaft 104carries the sprocket 107, driving the sprocket chain 108, for a purposeto be later described.

Although, in the preferred construction of my device, the shaft 7 isrotated to effect revolving of the rollers and knives, which are securedfor rotation therewith, it is apparent that shaft 7 may be stationaryand the rollers and knives mounted for rotation therearound by anysuitable drive mechanism, without departing from- The material, in thecase where heat is necessary to enhance compression thereof, is fed froma heater 109, into the chute 110, which leads the material into the diebowl. The heater is provided with a double jacketed bottom to form asteam chamber 111 for effecting heating of the material. Alongitudinally extending shaft 112, carrying the angularly disposedmixing and conveying paddles 113, is journaled in the end walls of theheater, and carries at its inner end the sprocket wheel 114, over whichchain 108 travels, so as to effect rotation of the shaft 112.

An opening 116 is provided in the inner end wall of the heater, throughwhich material flows into chute 110. To regulate the quantity ofmaterial which is forced through the opening 116,

' an adjustable gate 117 is slidably mounted, over said opening, in theguideways 118, as shown in Figure 11. A threaded spindle 119 is threadedto the gate 117, by any suitable means, and is journaled in the bearing121 secured to the heater. By turning handle 122 at the outer end ofspindle 119, the position of gate 117 may be readily adjusted.

Feeder posite end, which leads material into the heater from the feeder.

The conveyor screw is driven with a predetermined intermittent motionfor the purposes previously set forth. Any suitable drive mechanism maybe employed to perform this function. I prefer, however, to do this bymeans comprising the ratchet wheel 128 keyed for rotation to the end ofthe conveyor screw shaft 129, and which is adapted to be engaged by thespring pressed pawl 131. The pawl is mounted for slidable movement(Figure 13) in the guideway 132 on the inner side of the arm 133,journaled on the conveyor screw shaft 129. The free end of arm 133 ispivotedto the link 134, which in turn is pivoted to the arm 136, keyedfor rotation with the heater shaft 112. Upon rotation of arm 136, it isapparent that an oscillatory motion will be transmitted to the arm 133,and that the ratchet wheel 128 will be turned intermittently when thepawl 131 engagesin the teeth thereof.

To control the degree of turning of the ratchet wheel 128 andconsequently that of the screw conveyor 123, I preferably employ anadjustable cam structure, comprising the plate 137, having the flatsemicircular projection 138 at one side and the flange 139 forming anarcuate cam on the opposite side. The plate 137 is journaled formovement about the conveyor screw shaft 129, and when held in thepredetermined position desired, a pin 141, secured to the pawl 131, willride over cam flange 139, to thus disengage the pawl and ratchetmechanism for the purpose described.

semicircular projection 138 on plate 137, is formed with a plurality ofarcuately disposed apertures 142 at the bottom thereof; and the plate137 is held in the selected position by means of a removable pin 143passing through the selected aperture 142, and through an aperture in aretaining plate 144, secured below the cam structure, onto the upright146 forming part of the support for heater 109.

I have described by apparatus wherein a heater and feeder are bothemployed, the heater being desirable in the case where heat is requiredto enhance compressing of the material. If the material requires no heatto perform the latter function, it is obvious that the heater may beomitted. However, if it is intended to make blended pellets consistingof two or more materials, it is preferred to employ the heater, withoutadmitting steam thereto, for the purpose of effecting mixing of thematerial by means of the paddles 113 therein. r

Although I have described, for the purposes of ilustration, the deviceshown by the drawings, it is apparent that such'apparatus' may assumedifferent forms within the scope of the following which I claim as myinvention.

I claim:

' 1. In apparatus of the class described, a shaft, a die plate having anaperture through which the shaft passes, means for supporting the dieplate, a plurality of rollers supported by said shaft and adjacent oneface of the die for compressing and forcing material through aperturesin said die, a knife for cutting the material into pellets as it isextruded from said die, and means for rotating the rollers and knifeabout the shaft 2. In apparatus of the class described, a shaft, a dieplate having an aperture through which the shaft passes, means forsupporting the die plate, a spider mounted for slidable movement alongsaid shaft and having a plurality of arms projecting therefrom, rollersjournaled onsaid arms for compressing and forcing material throughapertures in said die, means for rotating the rollers about the shaftaxis, and means for moving the spider relative to the die.

3. In apparatus of the class described, a shaft, a die plate having anaperture through which the shaft passes, a die block in said apertureand having a hub surrounding the shaft, means for supporting the dieplate at the outer edge thereof, means including an element secured tosaid hub adapted to bear against the adjoining faces of the die blockand the die plate, a plurality of rollers supported by said shaft forcompressing and forcing material through apertures in the die plate, andmeans for rotating the rollers about the shaft axis.

4. In apparatus of the class described, a shaft, a die plate having, anaperture through which the shaft passes, said plate being capable ofreverse positioning whereby either face thereof may be exposed for use,a die block in said aperture and having a hub surrounding the shaft,means for supporting the die plate for reverse positioning at the outeredge thereof, means including an element secured to said hub adapted tobear against the adjoining faces of the die block and the die plate,- aplurality of rollers supported by said shaft for compressing and forcinga material through apertures in the die plate, and means for rotatingthe rollers about the shaft axis.

ing, a ring supported by said housing, a shaft mounted in said housing,a die plate having an aperture through which the shaft passes, a dieblock in said aperture and having a hub surrounding the shaft, means forsecuring the die plate at the outer edge thereof to said ring wherebythe ring and the die form a bowl, means for supporting the die block, aplurality of rollers supported by said shaft and in said bowl forcompressing and forcing material through apertures in the die plate, andmeans for rotating the rollers about the shaft axis.

6. In apparatus of the class described, a housing, an upright shaftmounted in said housing, means for journaling the shaft for rotation, ahorizontally positioned die plate having an aperture through which theshaft passes, means for 150 1 5. In apparatus of the class described, ahoussupporting the die plate, a plurality of rollers mounted formovement with said shaft and adapted to compress and force materialthrough apertures in the die, a knife mounted for movement with theshaft for cutting-the materialextruded from the die into pellets, andmeans for rotating the shaft.

'7. In apparatus of the class described, a housing, an upright shaftmounted in said housing, a thrust bearing adjacent the top of thehousing and in which the upper end of the shaft is journaled, means forsupporting the shaft in upright position, a horizontally positioned diehaving an aperture through which the shaft passes, means for supportingthe die, a bearing adjacent the lower end of the shaft, removable meansfor.

forming a rigid assembly of the latter bearing and die, a plurality ofrollers mounted for movement with said shaft and adapted to compress andforce material through apertures in the die, and means for rotating theshaft.

8. In apparatus of the class described, a die, a roller mounted formovement over the face of said die for compressing and forcing materialthrough apertures in said die, a plow, means for mounting said plow inthe path of movement of said roller, and means whereby the distancebetween said die and plow may be adjusted.

9. In apparatus of the class described, an upright shaft, means formounting said shaft, a horizontally positioned die plate having anaperture through which the shaft passes, means for supporting the dieplate, a plurality of rollers, means for mounting said rollers formovement over the face of the die and about the shaft axis forcompressing and forcing material through apertures in said, die, a plowfor each roller, means for mounting each of said plows in the path ofmovement of its roller, and means for simultaneously adjusting thedistance between said die and plows.

10. In apparatus of the class described, a die, a shaft positionedparallel to said die, a roller journaled on said shaft, means for movingthe shaft and roller over the face of said die for compressing andforcing material through apertures in said die, a plow frame, means formounting the plow frame in the path of movement of said roller, a plowin said frame, and means for mounting the plow for adjustment relativeto the die.

11. In apparatus of the class described, a shaft, a die plate having anaperture through which the shaft passes, means for removably securingthe.

die plate at the outer edge thereof, a die block in said aperture andhaving a hub surrounding the shaft, a split ring surrounding said huband adapted to bear against the adjoining faces of the die block and thedie plate, and a lock-nut threaded on said hub for holding the splitring, the diameter of the aperture being greater than that of thelock-nut.

12. In apparatus of theclass described, a shaft,

a die plate having an aperture through which the shaft passes, a dieblock in said aperture and adapted to close said aperture between saidshaft and die plate, independent means for supporting the die block andthe die plate, a roller supported I by said shaft for compressing andforcing material through apertures int said die plate, and

means for rotating said roller about the shaft axis. Y 13. In apparatusof the class described, a shaft, a die plate having an aperture throughwhich the shaft passes, a die block in said aperture, means forsupporting said die plate at the outer edge thereof, means surroundingsaid shaft and adapted to bear against the adjoining faces of the dieblock and the die plate, a roller supported by said shaft forcompressing and forcing material through apertures in said die plate,and means for rotating the roller about the shaft axis.

14. In apparatus of the class described a shaft, a die plate having anaperture through which the shaft passes, a die block in said apertureand having upper and lower surfaces flush with those of said die plate,means for supporting said die plate at the outer edge thereof, meanssurrounding said shaft and adapted to bear against the adjoining facesof the die block and the die plate, a roller supported by said shaft forcompressing and forcing material through apertures in said die plate,and means for rotating the roller about the shaft axis.

15. In apparatus of the class described a shaft, a die plate having anaperture through which the shaft passes, means for removably securingthe die plate at the outer edge thereof, a die block in said aperture; asplit ring surrounding said shaft and adapted to bear against the ad.-joining edges of the die block and the die plate, means for holding saidsplit ring, said means being of less diameter than that of the centralaperture of the die plate whereby upon the-removal of said split ringthe die plate may be withdrawn thereover.

16. In apparatus of the class described a shaft, a die plate having anaperture through which the shaft passes, means for removably securingthe die plate at the outer edge thereof, a die block in said aperture, asplit ring surrounding said shaft and adapted to ,bear against the faceof the die plate at the inner edge thereof, and means of less diameter,than that of the central aperture of said die plate for holding saidsplit ring.

1'7. In apparatus of the class described a shaft, a die plate having anaperture through which the shaft passes, means for supporting the dieplate, a roller mounted adjacent one face of the die plate forcompressing and forcing material through apertures in said die plate,means for rotating the roller about the shaft axis, and means mounted onsaid shaft for vertically moving the roller relative to the die plate.

18. In apparatus of the class described a shaft,

a die plate having an aperture through which the shaft passes, means forsupporting the die EDGAR T. MEAKIN.

